Document Detail

Transport and metabolism of thiamine in Ehrlich ascites-carcinoma cells.
MedLine Citation:
PMID:  5964972     Owner:  NLM     Status:  MEDLINE    
1. Aerobic or anaerobic incubation at 37 degrees of Ehrlich ascites-carcinoma cells in Krebs-Ringer bicarbonate medium containing glucose and labelled thiamine results in accumulation in the cell of labelled thiamine, so that the concentration of total labelled thiamine in the cells greatly exceeds (by a factor 7) that in the medium. This concentration ratio is approximately constant for small initial external concentrations of labelled thiamine but diminishes when the latter exceed 0.4mum. 2. All the labelled thiamine in the tumour cells is present as thiamine phosphates. 3. The uptake of labelled thiamine is markedly diminished by decrease of temperature. At 9 degrees concentration ratio (cells/medium) 0.5 is observed whereas at 37 degrees the concentration ratio is 8.6. 4. The extent of phosphorylation of labelled thiamine depends on the period of incubation. 5. The influx of labelled thiamine is diminished by the presence of its analogues, pyrithiamine and Amprol, and also by the presence of thiamine monophosphate and thiamine diphosphate, which are potent inhibitors of thiamine phosphorylation in Ehrlich ascites cells. 6. Labelled thiamine phosphates leak from the cell into the medium, so that eventually all the labelled thiamine, both in the cell and medium, is converted into thiamine phosphates. However, in the presence of 2,4-dinitrophenol (0.1mm) and iodoacetate (1mm) thiamine phosphorylation is diminished, the concentration ratio for labelled thiamine (cells/medium) falls to half its normal value and little or no labelled thiamine phosphates leaks into the medium. 7. In the presence of thiamine phosphates, free labelled thiamine accumulates in Ehrlich ascites cells against a concentration gradient, concentration ratios (cells/medium) greater than unity being evident. 8. The evidence supports the conclusion that thiamine is transferred into the Ehrlich ascites cell by a carrier-mediated energy-assisted process.
I A Menon; J H Quastel
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Biochemical journal     Volume:  99     ISSN:  0264-6021     ISO Abbreviation:  Biochem. J.     Publication Date:  1966 Jun 
Date Detail:
Created Date:  1967-07-02     Completed Date:  1967-07-02     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  2984726R     Medline TA:  Biochem J     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  766-75     Citation Subset:  IM    
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MeSH Terms
Biological Transport
Carbon Isotopes
Carcinoma, Ehrlich Tumor / metabolism*
Dinitrophenols / pharmacology
Iodoacetates / pharmacology
Sodium / pharmacology
Thiamine / metabolism*
Reg. No./Substance:
0/Carbon Isotopes; 0/Dinitrophenols; 0/Iodoacetates; 59-43-8/Thiamine; 7440-23-5/Sodium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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